TOPIC: Force Good News Bad News

Hi... I know that these are not Mercs(other than the fact that I can get parts at the Merc Dealer but I have to post it somewhere.

I was headed on a long 350 mile round trip down to Pennsylvania the other day to pick up a neat little '58 Alumacraft F2 with rear console steering. Up early before I took off, I checked Craigs in Binghamton which was on my way and saw an ad for two '89 Force Motors...a 50hp and 35hp for $200. Sounded too good to be true but I called and stopped on my way home.

The 50 was complete with attached controls/key and the 35 had no controls and the lower unit was off. He said he had the 50 running on his boat but the lower unit seals were leaking bad so he he bought the 35 cheap and used it's lower unit. Said he did fire up the 35. No time for compression checks etc and for $200 I figured I couldn't go wrong grabbing them both.

Started with the 50 yesterday and it had great compression(both cyls near 145) and good spark so I hooked it up on the muffs and fired it up. Ran pretty good but muffs didn't fit the curved foot too well and was only spitting a bit of water and getting hot so I shut it down and replaced the impeller today. Old one was ok and probably fine btw. Used a barrel and it is running real good.
Now for the Issue....the 35. jumped the starter with the battery and had good spark on both and top cyl 120. Great..not...bottom cyl had 30-40. Here we go. So I hooked up the small tank with heavy volume of oil and seafoam ....connected the hose to the water intake pipe and it fired right up albeit at a pretty high idle and of course choked out at lower rpms. So I let it warm up and loaded up the premix squirt bottle I use with a lot of seafoam and some marvs mystery. Squirted into the warm lower plug hole ...rotated the flywheel and squirted some more and put the plug back in and let it sit for a while .

Fired it back up later and of course it was smokin like crazy and seemed to be running a bit better but not right at slow idle..was hoping it might be just dirty carb....wishful thinking.

Checked compression again after letting it run for 15 mins or so and even though it had climbed to about 75-80 psi obviously still an issue.

Now to my question.... Should I consider just parting it out or maybe tear it apart and see what the issue is and maybe get away with something simple like new rings or something minor? Pull the head cover and peer in?

I've been turning wrench's on outboards for many years and many motors now but never got into the final mile of cracking the block and playing with crank and pistons...btw. Maybe a good time to learn?

Thanks for any ideas and suggestions in advance.

Tim, the forces had a tendency to carbon up badly. The rings on the bottom cyl are likely stuck. Good time to get your hands dirty and pull it apart. If it is too far gone inside then you can part it out.

I had a Force 35 about 3 years ago that I'd gotten as a freebie due to low compression. I planned on stripping it for parts and when I pulled the head discovered a blown head gasket. Replaced the gasket and compression came up and evened out. Motor ran beautifully! Certainly worth a look on yours.

If yours is blown, it's not worth rebuilding. Keep anything that's similar to the 50 for parts (ignition bits, lower unit, etc.) and part out the rest...

Dave...thanks for the advice.

Scott...interesting. Question...are you talking about the gasket between the powerhead and the lower pan or the gasket on the cyl heads? Every time I have pulled a power head out the gasket was always stuck and tore when I did so. therefore hard to tell.

I am betting you mean the cyl head gasket ...as in #37 here:
www.crowleymarine.com/mercury-outboard/parts/1280_12.cfm

Yea I am positive....so how did you know it was blown exactly? Can I test it some how for leakage before I take the head off?

If that is the issue I will be very happy. This is a nice clean engine and running albeit despite the low compression issue.

Thanks as always.

Tim

low compression on both cyl and the same i about 99% a blown head gasket between the 2 cyl. other wise pull the head.

Dave....it began with 120 on top and 40 on bottom. After soaking with marv's oil and seafoam and running etc the bottom got to 70-80. Its the bottom that is the issue not both.

But thanks and I suspect pulling it will be the overall answer.
Tim

Ain't gonna hurt to pull the cylinder head for a looksee.

Well Scott I didn't get as lucky as you did. I pulled the head and first noticed that it was not the gasket that had blown...it was fine. But it was immediately evident what was wrong. The lower cyl wall has a gouged out trench in it as seen here:

And here:

When rotating the crank it is easy to see the effect....on the compression stroke you can see and hear the air and oil spitting out that gap. Not really sure what is causing it...doesn't seem to be excessive play in the piston or a broken ring that I can see.

So now what? Option one...hope the gouge isn't too deep that it can be honed and add an oversized piston(kinda doubt it) or option two: tear it all apart and part it out by piece.

Too bad cause it is a nice clean looking motor that as I said is running albeit labored because of the pressure loss.

Thoughts?

In the mean time I'll go back to working on the 40 Scott or maybe my newest find yesterday...a really nice clean white '63 Merc 500. Wiring harness and cables and internal wiring is in great shape. Looks like new plug wires and fuel lines too. Only issue or blemish is that I see 3 of the 4 plug holes have heli-coils in them...hope they did them correctly and didn't drop any metal into the powerhead.

Spent a little bored time late last night cleaning up the Scott hood. Very nice all original motor this one is...gonna have to doll it up right.

Tim, it looks to me as if the head gasket was leaking right in line with that "wear" spot. Maybe a hot spot. Put a used ring in over the wear spot and measure the gap underneath, my guess is you would have to go .015 over to fix it. It kinda looks like the work of a dremmel tool in the wrong hands.

a good machine shop can offset bore the cyl so you can bore to
the smallest size possible have done this with H-D cyl
Charles